Cornelius Nepos was a Roman historian who lived during the 1st century BCE. He is best known for his work "De Viris Illustribus," which translates to "On Famous Men." This collection of biographies focused on notable figures from both Roman and Greek history, providing insights into their lives and achievements. Nepos is often credited with being one of the earliest biographers, influencing later writers like Plutarch. His style was straightforward and accessible, making his biographies popular among readers. Although many of his works have been lost, his contributions to historical writing remain significant in the study of ancient history.